Aircraft skin thickness online laser measurement method and system

Abstract

The invention relates to an aircraft skin thickness online laser measurement method and system. The method comprises the steps of S10, path planning; step S20, pre-scanning is carried out; step S30, generating a detection template; step S40, performing measurement; step S50, data processing; step S60, generating a report; the system comprises a data acquisition terminal and data acquisition and quality analysis software, the data acquisition terminal comprises a main shaft, a lithium battery, a control panel and a laser displacement sensor; the data acquisition and quality analysis software comprises a single chip microcomputer fixing program, a model management program and an automatic detection program; according to the invention, the nondestructive detection of the thickness of the whole skin can be rapidly and automatically completed at one time, and the method has the advantages of high detection precision, high detection efficiency, wide universality, traceable detection data, simultaneous processing and detection, portability and the like, meets the accurate, efficient and comprehensive measurement application requirements of the thickness of the aircraft skin, and improves the production efficiency for enterprises.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing and artificial intelligence, and in particular to an online laser measurement method and system for aircraft skin thickness. Background Art

[0002] With the rapid development of my country's aerospace industry, the demand for product quality is becoming increasingly stringent. During aircraft manufacturing, aircraft skin is the outer surface material covering the aircraft's fuselage structure. As a critical component protecting the aircraft's internal structures and systems, it withstands a variety of external factors during flight, including pressure, temperature fluctuations, and mechanical stress. The quality of this skin directly impacts the performance and service life of the product. Therefore, accurately measuring skin thickness is a crucial step in ensuring product quality.

[0003] Traditionally, aircraft skin thickness is measured manually using ultrasonic testing. This method presents several challenges. First, manual measurement is cumbersome and inefficient, requiring significant human resources and time. Furthermore, contact testing can easily damage the aircraft skin. Second, due to the complex shape and structure of aircraft skin, manual inspection is highly subjective and may not fully cover all areas, leading to the inability to detect localized thickness variations in time. Furthermore, manual measurement lacks accurate digital data, making traceable inspection data difficult to conduct quantitative analysis and make maintenance decisions. Summary of the Invention

[0004] The purpose of the present invention is to provide an online laser measurement method and system for aircraft skin thickness to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An online laser measurement method for aircraft skin thickness comprises the following steps:

[0007] Step S10: Path planning: calibrate the starting position of the data acquisition terminal and plan the serpentine detection path of the aircraft skin surface according to the detection site environment and the aircraft skin model, and write the G code of the CNC machine tool traction machine movement path;

[0008] Step S20: pre-scanning, starting the CNC machine tool traction machine to run according to the planned path, and after the operation is completed, exporting the effective time-position data table of the CNC machine tool traction machine;

[0009] Step S30: generating a test template, performing surface mesh feature recognition on the STL format model file of the aircraft skin to be tested, using a progressive data organization model method to obtain the standard thickness value of each test point of the aircraft skin to be tested, and setting test parameters to generate a test template;

[0010] Step S40: measurement implementation. After the test starts, the data acquisition terminal follows the CNC machine tool traction machine to scan the aircraft skin to be tested along a specified path and obtains scan data;

[0011] Step S50: Data processing, using a coordinate shift compensation algorithm to process the scanned data, matching the time of each detection point in the scanned data with the time in the time-position data table, thereby obtaining the detection value of each detection point, and comparing the detection value with the standard value to determine whether the thickness value of the detection point is out of tolerance;

[0012] Step S60: Generate a report, the inspection report includes an inspection report form, a color thickness map, an out-of-tolerance position map, a review point position map and a review table.

[0013] As a further explanation of the invention, step S30 includes the following steps:

[0014] Step S301: importing the STL format model file of the aircraft skin to be tested into the model management program of the data acquisition and quality analysis software, and performing surface mesh feature recognition;

[0015] Step S302: using a progressive data organization model method to determine the positional relationship between the detection point and the identified surface grid features, thereby obtaining the standard thickness value of each detection point of the aircraft skin to be tested;

[0016] Step S303: setting detection parameters including detection line spacing, detection point density, starting line offset, and detection speed through the detection template management module of the data acquisition and quality analysis software, and importing the time-position data table to generate a detection template.

[0017] As a further explanation of the invention, the method of identifying the surface mesh features of the aircraft skin to be tested in step 301 includes the following steps:

[0018] The imported STL format model file is preprocessed, including extracting the model's triangular facet information, moving the model to the origin of its own coordinate system, and performing data conversion; each processing surface is determined according to the height of the aircraft skin processing layer; then each processing surface is processed in a multi-threaded manner, and a method combining the adjacent edge midpoint matching method and the divide-and-conquer method is adopted to generate the mesh outline and hole boundary.

[0019] As a further illustration of the invention, step 302 includes the following steps:

[0020] The position coordinates of each detection point are compared with the area information in each data unit of the processing surface, grid contour, and hole boundary in turn to determine which processing surface the detection point belongs to, then determine which grid the detection point is located in, and then determine which contour the detection point is located in. The ray method is used to determine whether the detection point is within the contour. Only the data within the contour is a valid detection point. The detection point outside the contour, at the contour vertex, and at the contour edge are all invalid points. The detection points in the hole are eliminated, thereby obtaining the standard thickness value of each detection point of the aircraft skin to be tested.

[0021] As a further explanation of the invention, step S40 includes the following steps:

[0022] Step S401: Reset the CNC machine tool traction machine, drive the data acquisition terminal to move above the starting position and run according to the planned path, place the standard block directly above the aircraft skin detection point to be tested, and align the laser displacement sensor of the data acquisition terminal with the center of the standard block to ensure measurement accuracy;

[0023] Step S402: The data acquisition terminal is connected to the main control computer via the fixed program of the single-chip microcomputer of the data acquisition and quality analysis software. The CNC machine tool traction machine drives the data acquisition terminal to move downward according to the planned path. The automatic detection program of the data acquisition and quality analysis software determines the motion state of the data acquisition terminal through the transformation of the motion feedback data of the data acquisition terminal. The time of a certain position in the scanning process is matched with the start time in the time-position data table using an efficient time reference point calculation algorithm to determine the starting time reference point.

[0024] Step S403: After the detection starts, the data acquisition terminal follows the CNC machine tool traction machine to scan the aircraft skin to be tested along the specified path, and the automatic detection module displays the scanning data in real time until all the detection points in the detection template are scanned. The detection ends.

[0025] As a further illustration of the invention, the step 50 of processing data using a coordinate shift compensation algorithm includes the following steps:

[0026] The data of each scan line is counted, and the scan data that is too large is eliminated as invalid data based on the surface mesh characteristics of the aircraft skin to be tested. Then, the valid data segment is moved within the pre-reserved process margin range, and each scan line is iteratively processed until the solution with the most valid data is found. This result is used as the scan value of this scan line, and the test value is compared with the standard value to determine whether the thickness value of the test point is out of tolerance.

[0027] As a further illustration of the invention, the step 60 of generating a test report includes the following steps:

[0028] After the test is completed, the test statistics, color thickness map, out-of-specification point location map, check point distribution map, out-of-specification point list and check point list are inserted into the report template and stored as a test report file, thereby generating a test report.

[0029] As a further explanation of the invention, when calibrating the starting position of the data acquisition terminal, it is necessary to plan the Z-axis descent operation route of the CNC machine tool traction machine; when planning the serpentine detection path of the aircraft skin surface, it is necessary to reserve a process margin.

[0030] An aircraft skin thickness online laser measurement system, comprising any of the above-mentioned aircraft skin thickness online laser measurement methods, including a data acquisition terminal and a main control computer, wherein the main control computer is provided with data acquisition and quality analysis software;

[0031] The data acquisition terminal includes a spindle, a lithium battery, a control board and a laser displacement sensor; the spindle is set on the tool handle of the CNC machine tool, and the data acquisition terminal is driven by the CNC machine tool traction machine to move to detect the entire aircraft skin to be tested; the laser displacement sensor is set below the spindle, the lithium battery is used for power supply, the laser displacement sensor is communicated with the control board, and the control board is communicated with the main control computer.

[0032] As a further illustration of the invention, the data acquisition and quality analysis software includes a single chip fixed program, a model management program, and an automatic detection program;

[0033] The fixed program of the single-chip microcomputer includes six modules: an initialization module, a task processing module, an interrupt processing module, a laser displacement sensor command execution module, a wireless communication command execution module, and a data buffer maintenance and management module. The initialization module is used to initialize the IO port of the single-chip microcomputer; the task processing module is used for serial port data processing; the interrupt processing module is used to set a flag bit in the corresponding interrupt processing program; the laser displacement sensor command execution module is used to issue a working instruction to the laser displacement sensor; the wireless communication command execution module is used to set the working mode, connect to the wireless gateway, forward commands and read data; and the data buffer management module is used to temporarily store serial port instructions, laser displacement sensor commands and wireless communication commands.

[0034] The model management program includes a model management module and a detection template management module; the model management module is used to input the STL format model file of the aircraft skin to be tested, identify the surface mesh features of the aircraft skin, use the progressive data organization model method to obtain the standard thickness value of each detection point of the aircraft skin to be tested, and store the model data in the database; the detection template management module is used to create, modify and delete the detection template;

[0035] The automatic detection program includes a wireless communication module, a component detection module, and a model display module; the wireless communication module is used to configure wireless module parameters, send control commands, send and receive data packets, and pack and unpack data packets; the component detection module is used to read the skin data of the aircraft to be tested, automatically detect and control, solve data, save data, and output reports. The functions cooperate with each other to complete the detection of the aircraft skin; the model display module is used to display the scanning data of the aircraft skin to be tested.

[0036] Compared with the prior art, the present invention has the following beneficial technical effects:

[0037] The present invention provides an integrated technology that combines surface mesh feature recognition technology, progressive data organization model technology, high-precision time reference point solution algorithm and coordinate shift compensation algorithm with STL format model files, realizing one-time rapid and automatic non-destructive testing of the thickness of the entire skin. The technology has the advantages of high testing accuracy, high testing efficiency, wide applicability, traceability of testing data, testing while processing, and portability, meeting the application requirements of accurate, efficient and comprehensive measurement of aircraft skin thickness, and improving production efficiency for enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention.

[0039] Figure 1 2 is a schematic diagram of the principle of an online laser measurement system for aircraft skin thickness according to an embodiment of the present invention;

[0040] Figure 2 Schematic diagram of a serpentine detection path on an aircraft skin surface according to an embodiment of the present invention;

[0041] Figure 3 2. It is a schematic diagram of the framework of an online laser measurement system for aircraft skin thickness according to an embodiment of the present invention;

[0042] Figure 4 This is a flow chart of the on-line laser measurement method for aircraft skin thickness in an embodiment of the present invention.

[0043] In the figure: 10, data acquisition terminal; 20, single-chip computer fixed program; 30, model management program; 40, automatic detection program; 101, spindle; 102, lithium battery; 103, control board; 104, laser displacement sensor. DETAILED DESCRIPTION

[0044] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] like Figure 1-4 As shown, an embodiment of the present invention provides an online laser measurement method for aircraft skin thickness, comprising the following steps:

[0046] Step S10: Path planning, calibrate the starting position of the data acquisition terminal according to the detection site environment and aircraft skin model (by Figure 2 The "origin" in the figure represents the origin) and the aircraft skin surface serpentine detection path planning, and the preparation of CNC machine tool traction machine movement path G code;

[0047] Step S20: Pre-scan, start the CNC machine tool traction machine to run according to the planned path, and after the operation is completed, export the effective time-position data table of the CNC machine tool traction machine; provide the location information of each detection point to ensure the traceability of the detection data;

[0048] Step S30: generating a test template, performing surface mesh feature recognition on the STL format model file of the aircraft skin to be tested, using a progressive data organization model method to obtain the standard thickness value of each test point of the aircraft skin to be tested, and setting test parameters to generate a test template;

[0049] Step S40: measurement implementation. After the test starts, the data acquisition terminal follows the CNC machine tool traction machine to scan the aircraft skin to be tested along a specified path and obtains the scan data;

[0050] Step S50: Data processing, using a coordinate shift compensation algorithm to process the scanned data, matching the time of each detection point in the scanned data with the time in the time-position data table, thereby obtaining the detection value of each detection point, and comparing the detection value with the standard value to determine whether the thickness value of the detection point is out of tolerance;

[0051] Step S60: Generate a report, the inspection report includes an inspection report form, a color thickness map, an out-of-tolerance position map, a review point position map and a review table.

[0052] Furthermore, step S30 provided in this embodiment includes the following steps:

[0053] Step S301: importing the STL format model file of the aircraft skin to be tested into the model management program of the data acquisition and quality analysis software, and performing surface mesh feature recognition;

[0054] Step S302: using a progressive data organization model method to determine the positional relationship between the detection point and the identified surface grid features, thereby obtaining the standard thickness value of each detection point of the aircraft skin to be tested;

[0055] Step S303: Setting detection parameters including detection line spacing, detection point density, starting line offset, and detection speed through the detection template management module of the data acquisition and quality analysis software, and importing the time-position data table to generate a detection template.

[0056] Furthermore, step 301 provided in this embodiment, identifying the surface mesh features of the aircraft skin to be tested, includes the following steps:

[0057] The imported STL model file is pre-processed, including extracting model triangular facet information, moving the model to its own coordinate system origin, and performing data conversion. Each processing surface is determined based on the height of the aircraft skin processing layer. Each processing surface is then processed in a multi-threaded manner, using a combination of adjacent edge midpoint matching and a divide-and-conquer approach to generate mesh contours and hole boundaries. This achieves intelligent, step-by-step extraction of the processing surface, mesh contours, and hole boundary features of complex panels.

[0058] Furthermore, step 302 provided in this embodiment includes the following steps:

[0059] The position coordinates of each detection point are compared with the area information in each data unit of the processing surface, grid contour, and hole boundary in turn to determine which processing surface the detection point belongs to, then determine which grid the detection point is located in, and then determine which contour the detection point is located in. The ray method is used to determine whether the detection point is within the contour. Only the data within the contour is a valid detection point. The detection point located outside the contour, at the contour vertex, and at the contour edge is an invalid point. The detection point in the hole is eliminated, and the position of each detection point on the aircraft skin to be tested is accurately matched with the corresponding position of the surface grid feature after identification, so as to obtain the standard thickness value of each detection point on the aircraft skin to be tested.

[0060] Furthermore, step S40 provided in this embodiment includes the following steps:

[0061] Step S401: Reset the CNC machine tool traction machine, drive the data acquisition terminal to move above the starting position and run according to the planned path, place the standard block directly above the detection point of the aircraft skin to be tested, and align the laser displacement sensor of the data acquisition terminal with the center of the standard block to ensure measurement accuracy; that is, use the standard block as a reference and adopt the laser displacement sensor triangulation method. The thickness of the standard block is known, and the laser displacement sensor measures the sum of the thickness of the standard block and the aircraft skin, thereby inferring the thickness value of each detection point, ensuring the accuracy and repeatability of the measurement process; so that when the aircraft skin workpiece to be tested is detected to have a thickness deviation, it can be processed to achieve detection while processing.

[0062] Step S402: The data acquisition terminal is connected to the main control computer through the fixed program of the single-chip microcomputer of the data acquisition and quality analysis software. The CNC machine tool traction machine drives the data acquisition terminal downward according to the planned path. The automatic detection program of the data acquisition and quality analysis software determines the motion state of the data acquisition terminal through the transformation of the motion feedback data of the data acquisition terminal. An efficient time reference point solution algorithm is used to match the time of a certain position in the scanning process with the starting time in the time-position data table to determine the starting time reference point, thereby ensuring that the starting point of the data acquisition terminal coincides with the calibrated starting position when the detection starts.

[0063] Step S403: After the test starts, the data acquisition terminal follows the CNC machine tool traction machine to scan the aircraft skin to be tested along the specified path, and the automatic detection module displays the scan data in real time until all the detection points in the detection template are scanned. The test ends.

[0064] Furthermore, in step 50 provided in this embodiment, due to the low time precision of the motion control of the CNC machine tool, deviations may occur during operation according to the planned path, and it is impossible to accurately match the time of each detection point in the scan data with the time in the time-position data table. Therefore, the coordinate shift compensation algorithm is used to perform data processing, which includes the following steps:

[0065] The data of each scan line is counted, and the scan data that is too large is eliminated as invalid data based on the surface mesh characteristics of the aircraft skin to be tested. Then, the valid data segment is moved within the pre-reserved process margin range, and each scan line is iteratively processed until the solution with the most valid data is found. This result is used as the scan value of this scan line, and the test value is compared with the standard value to determine whether the thickness value of the test point is out of tolerance.

[0066] Furthermore, in step 60 provided in this embodiment, generating a test report includes the following steps:

[0067] After the test is completed, the test statistics, color thickness map, out-of-standard point location map, check point distribution map, out-of-standard point list and check point list are inserted into the report template and stored as a test report file, thereby generating a test report; among them, the color thickness map is a color map of the thickness difference of the test value, and each test point is displayed by calculating its corresponding color according to its processing error.

[0068] Furthermore, when calibrating the starting position of the data acquisition terminal, it is necessary to plan the Z-axis descent route of the CNC machine tool traction machine; ensure that the main control computer can search for data changes to determine the starting position of the data acquisition terminal; and reserve process margins when planning the serpentine detection path on the aircraft skin surface to prepare for subsequent data processing.

[0069] An aircraft skin thickness online laser measurement system includes the aircraft skin thickness online laser measurement method as described above, a data acquisition terminal and a main control computer, and the main control computer is provided with data acquisition and quality analysis software;

[0070] The data acquisition terminal includes a spindle, a lithium battery, a control board and a laser displacement sensor; the spindle is set on the tool handle of the CNC machine tool, and the CNC machine tool traction machine drives the data acquisition terminal to move to detect the entire aircraft skin to be tested; a laser displacement sensor is set under the spindle, and the lithium battery is used for power supply. The laser displacement sensor is connected to the control board for communication, and the control board is connected to the main control computer for communication; the control board includes the main control MCU (microcontroller unit) and peripheral control circuits. The laser displacement sensor continuously outputs the measurement data of the aircraft skin to be tested to the control board, and the control board then sends this data to the data acquisition and quality analysis software for processing.

[0071] Data acquisition and quality analysis software includes single chip computer fixed program, model management program and automatic detection program;

[0072] The fixed program of the single-chip microcomputer includes six modules: initialization module, task processing module, interrupt processing module, laser displacement sensor command execution module, wireless communication command execution module and data buffer maintenance management module; the initialization module is used to initialize the single-chip microcomputer IO port (single-chip microcomputer input / output device interface); the task processing module is used for serial port data processing; the interrupt processing module is used to set the flag bit in the corresponding interrupt processing program; the laser displacement sensor command execution module is used to issue working instructions to the laser displacement sensor; the wireless communication command execution module is used to set the working mode, connect to the wireless gateway, forward commands and read data; the data buffer management module is used to temporarily store serial port instructions, laser displacement sensor commands and wireless communication commands; and realize the joint control of the data acquisition terminal 10.

[0073] The model management program includes a model management module and a test template management module; the model management module is used to input the STL format model file of the aircraft skin to be tested, identify the surface mesh features of the aircraft skin, use the progressive data organization model method to obtain the standard thickness value of each test point of the aircraft skin to be tested, and store the model data in the database; the test template management module is used to create, modify and delete the test template;

[0074] The automatic detection program includes a wireless communication module, a component detection module, and a model display module; the wireless communication module is used to configure wireless module parameters, send control commands, send and receive data packets, and pack and unpack data packets; the component detection module is used to read the skin data of the aircraft to be tested, automatically detect and control, solve data, save data, and output reports. The functions work together to complete the detection of the aircraft skin; the model display module is used to display the scanning data of the aircraft skin to be tested.

[0075] In summary, the embodiments of the present invention provide an integrated technology that combines surface mesh feature recognition technology, progressive data organization model technology, high-precision time reference point solution algorithm, and coordinate shift compensation algorithm with STL format model files, thereby realizing one-time rapid and automatic non-destructive testing of the thickness of the entire skin. In addition, the technology has the advantages of high detection accuracy, high detection efficiency, wide applicability, traceability of detection data, detection while processing, and portability, meeting the application requirements for accurate, efficient, and comprehensive measurement of aircraft skin thickness, thereby improving production efficiency for enterprises.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An online laser measurement method for aircraft skin thickness, characterized in that: The following steps are involved: Step S10: path planning, calibrating the starting position of the data acquisition terminal and planning the serpentine detection path of the aircraft skin surface according to the detection site environment and the aircraft skin model, and writing the G code of the CNC machine tool traction machine moving path; Step S20: pre-scanning, starting the CNC machine tool traction machine to run according to the planned path, and after the running is completed, exporting the effective time-position data table of the CNC machine tool traction machine; Step S30: Generate a detection template, perform surface mesh feature recognition on the STL format model file of the aircraft skin to be tested, use a progressive data organization model method to obtain the standard thickness value of each detection point of the aircraft skin to be tested, and set the detection parameters to generate a detection template; Step S40: measurement implementation, after the detection starts, the data acquisition terminal follows the CNC machine tool traction machine to scan the aircraft skin to be tested along a specified path and obtains the scanning data; Step S50: data processing, using a coordinate shift compensation algorithm to process the scanned data, matching the time of each detection point of the scanned data with the time of the time-position data table, thereby obtaining the detection value of each detection point, and comparing the detection value with the standard value to determine whether the thickness value of the detection point exceeds the tolerance; Step S60: Generate a report, the test report includes a test report table, a color thickness map, an out-of-tolerance position map, a review point position map and a review table.

2. The on-line laser measurement method for aircraft skin thickness according to claim 1, characterized in that: The step S30 comprises the following steps: Step S301: importing the STL format model file of the aircraft skin to be tested into the model management program of the data acquisition and quality analysis software, and performing surface mesh feature recognition; Step S302: using a progressive data organization model method to determine the positional relationship between the detection point and the identified surface grid feature, thereby obtaining a standard thickness value of each detection point of the aircraft skin to be tested; Step S303: setting detection parameters including detection line spacing, detection point density, starting line offset, and detection speed through the detection template management module of the data acquisition and quality analysis software, and importing the time-position data table to generate a detection template.

3. The on-line laser measurement method for aircraft skin thickness according to claim 2, characterized in that: The step 301 of identifying the surface mesh features of the aircraft skin to be tested comprises the following steps: The imported STL format model file is preprocessed, including extracting the model triangle face information, moving the model to the origin of its own coordinate system, and performing data conversion; each processing surface is determined according to the height of the aircraft skin processing layer; then each processing surface is processed in a multi-threaded manner, and a combination of the adjacent edge midpoint matching method and the divide-and-conquer method is used to generate the mesh contour and hole boundary.

4. The on-line laser measurement method for aircraft skin thickness according to claim 3, characterized in that: The step 302 includes the following steps: The position coordinates of each detection point are compared with the area information in the data units of the processing surface, grid contour, and hole boundary in turn to determine which processing surface the detection point belongs to, and then determine which grid the detection point is located in, and then determine which contour the detection point is located in. The ray method is used to determine whether the detection point is within the contour. Only the data within the contour is a valid detection point. The detection points outside the contour, at the contour vertex, and at the contour edge are all invalid points. The detection points in the holes are eliminated, so as to obtain the standard thickness value of each detection point of the aircraft skin to be tested.

5. The on-line laser measurement method for aircraft skin thickness according to claim 4, characterized in that: The step S40 comprises the following steps: Step S401: Reset the CNC machine tool traction machine, drive the data acquisition terminal to move above the starting position and run according to the planned path, place the standard block just above the aircraft skin detection point to be tested, and align the laser displacement sensor of the data acquisition terminal with the center of the standard block to ensure measurement accuracy; Step S402: the data acquisition terminal is connected to the main control computer through the single-chip fixed program of the data acquisition and quality analysis software, the CNC machine tool traction machine drives the data acquisition terminal to move downward according to the planned path, the automatic detection program of the data acquisition and quality analysis software determines the motion state of the data acquisition terminal through the transformation of the motion feedback data of the data acquisition terminal, and uses an efficient time reference point solution algorithm to match the time of a certain position in the scanning process with the start time in the time-position data table to determine the start time reference point; Step S403: After the detection starts, the data acquisition terminal follows the CNC machine tool traction machine to scan the aircraft skin to be tested along a specified path, and the automatic detection module displays the scanning data in real time until all the detection points in the detection template are scanned, and the detection is completed.

6. The on-line laser measurement method for aircraft skin thickness according to claim 5, characterized in that: The step 50, using the coordinate shift compensation algorithm to perform data processing, includes the following steps: The data of each scan line is counted, and the scan data that is too large is eliminated as invalid data according to the surface mesh characteristics of the aircraft skin to be tested. Then, the valid data segment is moved within the pre-reserved process margin range, and each scan line is iteratively processed until the solution result with the most valid data is found. This result is used as the scan value of this scan line, and the test value is compared with the standard value to determine whether the thickness value of the test point is out of tolerance.

7. The on-line laser measurement method for aircraft skin thickness according to claim 6, characterized in that: The step 60 of generating a test report comprises the following steps: After the test is completed, the test statistics, color thickness map, out-of-specification point location map, check point distribution map, out-of-specification point list and check point list are inserted into the report template and stored as a test report file, thereby generating a test report.

8. The on-line laser measurement method for aircraft skin thickness according to claim 7, characterized in that: When calibrating the starting position of the data acquisition terminal, it is necessary to plan the Z-axis descent route of the CNC machine tool traction machine; when planning the serpentine detection path of the aircraft skin surface, it is necessary to reserve a process margin.

9. An aircraft skin thickness online laser measurement system, comprising an aircraft skin thickness online laser measurement method according to any one of claims 1 to 8, characterized in that: It includes a data acquisition terminal and a main control computer, wherein the main control computer is provided with data acquisition and quality analysis software; The data acquisition terminal includes a main shaft, a lithium battery, a control board and a laser displacement sensor; the main shaft is arranged on the tool handle of a CNC machine tool, and the data acquisition terminal is driven by the traction machine of the CNC machine tool to move to detect the entire aircraft skin to be tested; the laser displacement sensor is arranged under the main shaft, the lithium battery is used for power supply, the laser displacement sensor is communicatively connected to the control board, and the control board is communicatively connected to the main control computer.

10. The aircraft skin thickness online laser measurement system according to claim 9, characterized in that: The data acquisition and quality analysis software includes a single chip microcomputer fixed program, a model management program and an automatic detection program; The fixed program of the single-chip microcomputer includes six modules: initialization module, task processing module, interrupt processing module, laser displacement sensor command execution module, wireless communication command execution module and data buffer maintenance management module; the initialization module is used for initializing the IO port of the single-chip microcomputer; the task processing module is used for serial port data processing; the interrupt processing module is used to set the flag bit in the corresponding interrupt processing program; the laser displacement sensor command execution module is used to issue working instructions to the laser displacement sensor; the wireless communication command execution module is used to set the working mode, connect to the wireless gateway, forward commands and read data; the data buffer management module is used to temporarily store serial port instructions, laser displacement sensor commands and wireless communication commands; The model management program includes a model management module and a detection template management module; the model management module is used to input the STL format model file of the aircraft skin to be tested, identify the surface grid features of the aircraft skin, use the progressive data organization model method to obtain the standard thickness value of each detection point of the aircraft skin to be tested, and store the model data in the database; The detection template management module is used to create, modify and delete detection templates; The automatic detection program includes a wireless communication module, a component detection module, and a model display module; the wireless communication module is used for wireless module parameter configuration, sending control commands, receiving and sending data packets, and data packet packaging and unpacking; the component detection module is used for reading the aircraft skin data to be tested, automatic detection control, data solution, data storage and report output, and the functions cooperate with each other to complete the detection of the aircraft skin; the model display module is used to display the scanning data of the aircraft skin to be tested.

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